1. Field of the Invention
The present invention relates to a light-source device for an endoscope. More particularly, the present invention relates to a light-source for an endoscope, that comprises at least two lamps, and which is structured so that a burn out lamp can be exchanged with a new lamp.
2. Description of the Related Art
As is well known, an endoscope, in which an internal image is observed through an optical fiber scope, and an electronic endoscope, in which an internal image is reproduced on a TV monitor, both require a light-source device or an image-signal processing apparatus that is provided with a light-source device into which an image-signal processing unit is integrated. This is because endoscopy carried out by inserting an optical fiber scope or an electronic endoscope into a human body requires light to illuminate the internal organs.
Therefore, inside the optical fiber scope and the electronic endoscope, a light guide cable for transmitting illumination light is provided. The incident end of the light guide cable is optically connected to the light-source device, and the emitting end of the light guide cable is connected to an illumination optical system disposed at the distal end of the optical fiber scope and the electronic endoscope. Accordingly, the illumination light transmitted from the light-source device through the light guide cable is emitted from the distal end of the optical fiber scope or the electronic endoscope.
As a lamp of the light-source device of the endoscope, a white-light lamp, such as a halogen lamp, a xenon lamp, and the like, is used. When the lamp is burnt out during the endoscope observation, of course the observation is disabled, so that diagnosis using the endoscope or the electronic endoscope is interrupted. This interruption of the diagnosis imposes a burden on a patient and also makes the diagnosis inefficient, so that it should be avoided as far as possible. Particularly, although the price of a halogen lamp is cheaper than that of a xenon lamp, the life of a halogen lamp is considerably shorter, therefore when a halogen lamp is used, the above problem is matter of grave concern.
Accordingly, as disclosed in KOKAI No. 7-27012, a light-source device for an endoscope that is provided with two lamps, which can be switched from the first lamp to the second lamp immediately when the first lamp is burnt out, is already proposed. In this type of light-source device, the two lamps are provided on a turntable that is rotatably switched between the first position and the second position. When the position of the turntable is rotated and switched from the first position to the second position, the second lamp is optically connected to the light-source device and turned on. According to the above light-source device, the diagnosis can be substantially continued without interruption even when the first lamp is burnt out.